The salient feature of this isotropic relation is proximity. As the tones get farther apart from one another, the above or below-ness of tonal relations becomes increasing ambiguous.

In the following examples, each button is associated with a set of tone-pairs. Each set consists of four pairs. For each such group, you will hear a pair of tones, a brief pause, then another pair of tones, and so on for a total of four pairs. For each group, a single interval separates each of the two tones. However, the tones themselves will differ for each pair. Each of the groups (associated with a button) has its own characteristic interval. Moreover, each group will consist of only ascending or descending intervals, as indicated by the label on the button.

As you listen, notice which of the groups seems to have an ambiguous character in regards to whether the second tone of each pair is ascending or descending.

GROUP 1

GROUP 2

In Group 1, you will have observed that all the tone pairs labelled "Descending" were, indeed, descending, while those labeled "Ascending" were indeed ascending. The interval between each of these pairs is a semitone (or minor second). In this group the upness and downness of tones is unambiguous.

In Group 2, however, the upness and downness is becoming somewhat ambiguous, due to the greater distance separating each tone.